1. Field of the Invention
The present invention relates to a shutter holding mechanism for holding a focal-plane type shutter unit inside a camera body.
2. Description of the Related Art
Conventionally, it is common that an image pickup apparatus that picks up an optical image formed by an image pickup optical system using an image pickup device and the like (hereinafter referred to as a camera and the like) is configured by fixedly holding a shutter unit configured with a shutter blade (a light shielding blade) that opens and closes an optical path of the image pickup optical system and a driving mechanism, driving circuit and the like that drive the shutter blade at an appropriate timing, inside a camera body.
As the shutter unit provided in a conventional camera and the like, a so-called focal-plane type shutter unit is generally widespread which is configured, for example, by arranging the shutter blade traveling parallel to a light receiving surface of an image pickup device near a front surface side of the image pickup device.
In the conventional camera provided with the focal-plane type shutter unit, when the shutter blade is driven to perform an opening/closing operation of the shutter blade, for example, when the shutter blade starts traveling, travel reaction acts on a shutter frame member holding the shutter blade to cause this (the shutter frame member) to move in a direction opposite to the travel direction of the shutter blade. Further, when the travel of the shutter blade stops at a predetermined position, the shutter blade comes into contact with a predetermined fixed member in the travel direction, and there is a possibility that impact occurs. Furthermore, there may be a case that rotation-direction power is imposed on the shutter frame member at that time.
In such a case, when the power that occurs in the travel direction of the shutter blade at the time of driving the shutter unit is transmitted to a camera body side, it will cause the camera body to vibrate. Furthermore, there is a possibility that, when the vibration and the like are transmitted to an image pickup unit that includes the image pickup device and the like, a lens barrel and the like via the camera body, adverse effects such as image blur may occur in an acquired image as a result, and this has been a problem.
Therefore, in the conventional camera to which the focal-plane type shutter unit is applied, and the like, devices are made, such as providing a buffer member having elasticity between the camera body and the shutter unit at the time of fixedly holding the shutter unit inside the camera body. Due to the configuration, the shutter unit is permitted to move within a predetermined range. The configuration is made so that, by the travel reaction and the like of the shutter blade that occur at the time of driving the shutter unit acting on the shutter unit itself and causing this (the shutter unit) to move within the predetermined range, the vibration and the like that occur at the time of driving the shutter unit are absorbed.
As for the shutter holding mechanism in which devices for reducing and preventing vibration and the like that are caused by the power that occurs at the time of driving the shutter unit being transmitted to the camera body are made as described above, various kinds of such shutter holding mechanisms are proposed, for example, by Japanese Patent Application Laid-Open Publication No. 6-67259, Japanese Patent Application Laid-Open Publication No. 9-189939, Japanese Patent Application Laid-Open Publication No. 9-244099 and the like and have been put to practical use.